Liquid has an indefinite shape and adopts the shape of its container. Liquid flows from one location to another location due to force of gravity when there is a difference in potential energy and an available path. Liquid floats vehicles so that vehicle such as ships can travel across seas and oceans and from ports to ports. Liquid can be used as an energy source or energy generating source and can be stored. Hydroelectric power is an example of energy generated by liquid as a stored energy source. These and many other properties and characteristics of liquid are fascinating.